The present invention relates to remotely repairing files, and more specifically, to using hierarchical and segmented cyclic redundancy checks (CRC) to repair files.
In a typical application, a remote server stores a large inventory of files, one or more of which may be of interest to a local client. When the client requests and/or pays for information stored in the inventory of files, the remote server can transmit the file of interest to the local client. Thus, the server and the client maintain identical copies of the file of interest. However, the client copy of the file may become corrupted as a result of hardware and/or software malfunction, user error, or transmission error.
One reliable way to correct a corrupted file is to replace the entire file. Oftentimes, the file may be very large, e.g., in excess of 100 MB or more. This makes the process of transferring a replacement file over an existing transmission channel, such as the Internet, expensive and time consuming.
Conventional techniques, such as Rsync, exist which can handle, among other duties such as patching, the correction of a corrupted file. However, the cost of these techniques can be very expensive because the cost can include running and maintaining a sophisticated client-server protocol and the servers necessary to implement them, heavy bi-directional network traffic, security implications, and so on.